The present invention relates to an apnea monitoring and therapeutic system and more specifically a system directed at stimulation of a patient in respiratory distress.
The cessation of respiration or the inability to get one's breath often referred to as apnea, is a serious problem which becomes dangerous especially in premature infants where such occurrences are frequent. It is understood that repeated attacks as well as prolonged attacks of apnea are factors which carry a poor prognosis both for life and for subsequent mental development resulting from irreversible cerebral damage sustained during these apneic episodes. The best prospect of reducing harmful effects of late-occurring apnea is through constant surveillance preferably using some automated device to alert attendants so that stimulation through resuscitation can begin promptly. As a consequence, apnea monitoring of premature infants has become an accepted practice in most institutions.
Management of apnea monitoring in the newborn, particularly in prematures, for the most part includes sensitive devices for detecting apneic events. Upon detection of an apneic episode a visual or audible alarm is generated, to call the attending nurse for prompt manual stimulation of the infant in an attempt to terminate the episode by restoring normal breathing. Alertness and responsiveness of the nursing staff is improtant as it becomes more difficult to obtain a positive response to stimulation the longer the apnea persists. Naturally then, most apnea monitors are designed to provide an early alarm. Unfortunately, however, most of these apneic episodes are of a short duration and occur almost randomly during any day of neonatal life. Thus, they place an unnecessary burden on the nurse to the extent that in some cases it is conceivable that the alarms may even be neglected. There is a further difficulty inherent in the operation of most monitors. Breathing signals from the infant vary in amplitude and need to be adjusted for each infant. Unfortunately the signal also varies as the infant moves. Yet if the nurse adjusts sensitivity too high, heart beats are interpreted as breathing, with disasterous results. If the sensitivity is too low, shallow breathing triggers a false alarm, much to the annoyance of attending personnel.
In the instant case, these difficulties are avoided by adjustment of the device on the low side of sensitivity; former false alarms are now unnecessary stimulations. This tends to lessen the number of manual intrusions required by attending personnel, thereby attaching greater validity and importance to alarms.
The purpose of the present invention is to avoid some of the problems incurred in apnea monitoring by closing the loop of the automated monitoring system, to provide a therapeutic action by early stimulation of the respiratory distressed patient. The preferred innovative technique of automatic mechanical stimulation in the present embodiment is directed to suddenly induce a loss of equilibrium, for example, such as from a falling sensation to, in effect, startle the infant into a natural respiration pattern. This is conveniently accomplished by sudden inflation or deflation, through regulating the pneumatic pressure, of a small pneumatic mattress which is preferably placed under the upper half of the infant's body.